Trenching apparatus



June 18, 1968 R. B. PECK TRENCHING APPARATUS 3 Sheets-Sheet 2 Filed July16, 1965 Iii-Z- INVENTOR: RAYM 01m .5. PE CK A ys.

June 18, 1968 Q R. B. PECK 3,388,487

TRENCHING APPARATUS Filed July 16, 1965 S Sheets-Sheet 3 INVENTOR.RAYMDND B. PEEK.

ATTYS.

United States Patent 3,388,487 TRENCHING APPARATUS Raymond B. Peck, Rte.1, Holgate, Ohio 43527 Filed July 16, 1965, Ser. No. 472,610 Claims.(CI. 37-90) ABSTRACT OF THE DISCLOSURE Trenching apparatus for use witha self-propelled vehicle. The trenching apparatus includes a supportadjacent the rear of the vehicle. The support mounts a digger assemblyfor movement along a generally vertical guide path. The digger assemblyincludes a chain support member and a closed loop digging chain. Anearth backboard member is mounted interiorly of the chain loop and ashielding member is spaced forwardly of the backboard member. A portionof the earth backboard member and the shielding member define apassageway for excavated earth. Earth removal mechanism is mountedadjacent the vehicle and forwardly of the chain loop. The apparatus alsoincludes chain driving means and means for adjustably positioning thedigger assembly along the guide path.

This invention relates to excavating equipment and, more particularly,to improved trenching apparatus.

The present invention is an improved trencher which has the capabilityof digging a trench to an established grade. After the trench has beenexcavated, pipe may be laid in the trench without additional handdigging.

In some parts of this country, for example, in the region extendingbetween Cleveland, Ohio, and Fort Wayne, Ind., the terrain is generallyflat. It is not unusual for sanitary sewers or storm sewers to be laidat a 0.3 percent grade or less. Prior art automated trenching apparatusis incapable of accuately digging a trench having such a fiat grade.Furthermore, prior art trenchers are generally ineffective in excavatingtrenches to depths greater than four feet and are also ineffective indigging through rocky soil or hardpan. For this reason, when trenchesare dug at depths of seven feet or greater, it is common to use either adragline or a backhoe rather than a prior art trencher.

One type of prior art trencher is a trencher in which buckets aremounted at the rear of a vehicle and move in a circular, generallyvertical, path. As the buckets come upwardly, they excavate the trench.The buckets then continue upwardly and the excavated soil is dischargedon a conveyor as it begins its downward movement. An example of thistype of prior art trencher is disclosed in US. Patent 2,692,446.

Another type of prior art trencher is one having a cantilevered boomwhich extends from the rear end of a vehicle. An endless digger chainexcavates the trench. However, because the digger chain is open theexcavated soil is continually reworked. It is very difiicult to hold agrade with this type of trencher. This is particularly so whenexcavating, for example, hard clay. When the rear end of the boom islowered to take a deeper cut an upward force is created on the rearwheels of the vehicle. In severe conditions, the rear driving wheelshave been lifted from the ground and the movement of the digging chainhas moved the trencher backwards in the trench.

It is the primary object of the present invention to provide improvedtrenching apparatus having means for digging a trench to a predeterminedgrade.

It is another object of the instant invention to provide trenchingapparatus having an improved digger assembly whereby soil which has beenexcavated is prevented from falling backwardly into the trench.

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It is a still further object of the present invention to providetrenching apparatus which is extremely maneuverable and which has thecapability of digging trenches of relatively deep depth.

It is still another object of the present invention to provide trenchingapparatus having a support frame which is movable between a generallyvertical operating position and a generally horizontal travelingposition.

Still further objects of the present invention. will become apparentfrom the following specification and drawings in which:

FIG. 1 is a side view in elevation, partially in cross section, oftrenching apparatus, according to the present invention, and showing aportion of a trench which is being excavated;

FIG. 2 is a rear view of the trenching apparatus shown in FIG. 1, withsome of the parts omitted for clarity;

FIG. 3 is a sectional view taken along the line 33 of F IG. 2 and shownon an enlarged scale;

FIG. 4 is a view similar to FIG. 1, showing another embodiment of thepresent invention in which a section of the trenching apparatus supportframe is movable between a generally vertical operating position and agenerally horizontal traveling position; and

FIG. 5 is a fragmentary side view showing the jointed connection betweenthe upper and lower sections of the support frame, with portions omittedfor clarity and shown on an enlarged scale.

Briefly, the present invention relates to a trenching apparatusincluding a self-propelled vehicle. A longitudinally extending supportframe is mounted adjacent the rear end of the vehicle. The support framedefines a longitudinally extending guide path and a digger assembly ismounted for movement along the guide path. The digger assembly comprisesa chain support member, a closed loop digging chain mounted for movementon the chain support member, and an earth backboard member mountedinteriorly of the chain loop. Earth conveyor means are mounted adjacentthe vehicle exteriorly of the chain loop. The trenching apparatus alsoincludes means for driving the chain and means for adjustablypositioning the digger assembly along the guide path defined by thesupport frame.

Referring to FIG. 1 of the drawings, an improved trenching apparatusaccording to the present invention is indicated at 10. The trenchingapparatus 10 includes a self-propelled vehicle 11 having a pair of frontwheels 12 and a pair of rear wheels 13. The front wheels 12 are mountedon a front axle 14 and the rear wheels 13 are mounted on a rear axle 15.A chassis 16 is supported by the respective axles 14 and 15. An engine(not shown) is mounted on the chassis 16 and a transmission means,generally indicated by the reference number 17 is mounted on the chassis16. Preferably, the transmission means 17 is capable of enabling theself-propelled vehicle 11 to operate at high speeds duringtransportation of the trenching apparatus 10 and at low speeds when thetrenching apparatus 10 is in the operating position, as shown in FIG. 1.

v The transmission means 17 may consist of two separate 3-speedtransmissions, the first acting as a high speed transmission and thesecond acting as a low speed transmission, or in the alternative, aspecially designed unitary transmission having both high speed and lowspeed capabilities may be utilized.

A longitudinally extending, and generally vertical, support frame 20 ismounted on the chassis 16 adjacent the rear end of the self-propelledvehicle 11. In the present embodiment, the support frame 20 includesfour vertically extending angles 21 which are joined together by topwebs 22 and bottom webs 23. It should be understood that the supportframe 20 may be constructed of several configurations and materials, forexample tubular members may be used rather than the angles 21.

The interior surfaces of the angles 21 define a longitudinally extendingguide path, generally indicated by the reference number 24. A diggerassembly 25 is mounted interiorly of the angles 21 for movement alongthe guide path 24. The digger assembly 25 includes a longitudinallyextending chain support member 26 which comprises two opposed verticalplates 27 and 28 and a head member 29. The head member 29 is generallybox shaped and has an outer surface which is complementary with theguide path 24 defined by the angles 21. The plates 27 and 28 depend fromthe head member 29 and are spaced inwardly of the interior surfaces ofthe angles 21 (see FIG. 2).

An upper chain sprocket 30 is carried by a sprocket shaft 31 which ismounted for rotation on the head member 29. A lower chain sprocket 32 ismounted on a sprocket shaft 33 which extends between the opposed plates27 and 28 of the digger assembly 25. In the present embodiment, abracket 34 extends rearwardly from the opposed plates 27 and 28 andmounts an idler sprocket 35.

A closed loop digging chain 36 is mounted for movement on the chainsupport member 26. The digging chain 36 is supported by the upper chainsprocket 30, the lower chain sprocket 32, and the idler sprocket 35. Inthe instant embodiment, a single closed loop digging chain 36 is shown.However, a plurality of digging chains may be used. The number ofdigging chains used depends upon the trench width. If a trench having agreater width is desired two or more digging chains may be utilized.

The digging chain 36 includes a plurality of open cutting teeth 37. Thecutting teeth 37 are mounted at spaced intervals along the chain 36. Inthe present embodiment, the cutting teeth are shown as U-shaped members.However, they may be of other configurations, for example, L-shapedmembers.

An important feature of the present invention is an earth backboardmember 39 which, in the present embodiment, consists of a longitudinallyextending plate mounted on the opposed plates 27 and 28 of the chainsupport member 26. The backboard member 39 has a width slightly lessthan the width of the cutting teeth 37 (see FIG. 2) and extends from aposition immediately above the lower chain sprocket 32 upwardly to alocation immediately beneath the upper chain sprocket 30.

Referring to FIG. 1, the trenching apparatus 10 is shown digging atrench 40. As the earth is excavated by the cutting teeth 37, theexcavated soil or earth is moved upwardly and the backboard member 39prevents the excavated soil from falling downwardly into the excavatedportion of the trench 40 whereby the returned soil must be reworkedeither by another machine operation or by hand. While the chain supportmember 26 is shown in the present embodiment as a generally verticalmember, This type of digger assembly is equally suitable to acantilevered boom type structure which extends at an angle from the rearof a vehicle.

Referring to FIG. 1, a bracket 41 extends outwardly from the upper endof one of the angles 21, of the support frame 20, and mounts an idlerpulley 42. A continuous drive cable 43 extends around the idler pulley42 and thence downwardly around an idler pulley 44 which is mounted on astub shaft 45 which extends outwardly from the head member 29 of thechain support member 26. The drive cable 43 then extends upwardly arounda drive pulley sprocket 46 which i mounted on the sprocket shaft 31. Asthe drive pulley sprocket 46 rotates, the sprocket shaft 31 and theupper chain sprocket 30 also rotate, thus driving the closed loopdigging chain 36. The path of the drive cable 43 continues downwardlyaround an idler pulley 47 which is mounted on a stub shaft 48 whichextends outwardly from one of the bottom webs 23. The drive cable 43then extends around a driven sprocket 49 which is mounted on a drivenshaft 50. The driven shaft 50 is operatively connected to the vehicledrive shaft. The drive cable 43 also extends around an idler pulley 51which is supported by a bracket 52 which extends upwardly from thechassis 16. The path of the drive cable 43 then continues upwardlypassing over the idler pulley 42, thus completing the circuit.

The chain support member 26 moves vertically along the guide path 24defined by the support frame 20 and the drive cable path described aboveis designed to keep constant tension on the drive cable 43. As shown inFIG. 1, the idler pulley 44 and the drive pulley sprocket 46 are mountedon the head member 29 of the support member 26 and move with the supportmember 26. The remainder of the pulleys or sprockets remain in a fixedlocation.

Referring to FIG. 2, means for adjustably positioning the diggerassembly 25 along the guide path 24 are generally indicated by thereference number 55. The positioning means 55 includes a winch 56mounted on the support frame 20. Automated winches, for examples,electric or hydraulic winches are within the contemplation of thepresent invention. A winch cable 57 extends upwardly and passes over apair of idler pulleys 58 which are mounted on the top webs 22 of thesupport frame 20. An end 59 of the winch cable 57 is connected to thehead member 29 of the chain support member 26. When it is desired to diga trench to a deeper elevation, the cable 47 is extended and the chainsupport member 26 moves downwardly along the guide path 24 defined bythe support frame 20. Conversely, when a shallower depth is desired, thewinch 56 is operated and the cable 57 is retracted thus raising thechain support member 26. Because the digging action of the chain 36creates a downward reaction on the support member 26, the cable 57remains in tension or in a taut position throughout the diggingoperation.

Means for correlating the vertical position of the digger assembly 25with an established grade, for example, a surveyors sewer grade, isindicated by the reference number 60 (see FIG. 2). The corrrelatingmeans 60 includes a bracket 61 which is mounted on and extends outwardlyfrom the head member 29. The bracket 61 moves upwardly and downwardlywith the chain support member 26. The bracket 61 mounts a sightbar 62which has a longitudinally extending horizontal run (not shown) alongits bottom edge. The horizontal run of the sightbar is positioned apredetermined distance above the bottom of the cutting chain 36 asindicated by the reference number 37a in FIG. 2. As is well known, whensanitary sewers or the like are installed on a predetermined grade, asurveyor sets a grade line which runs parallel to the center line of thetrench, or in the alternative, a series of batter boards which runtransversely of the trench at predetermined spaced intervals. Whenutilizing the trenching apparatus 10, an operator establishes a datumplane which is a given distance above the established grade line of thesewer. The distance between the data plane and the grade line of thesewer is equal to the predetermined distance between the bottom of thedigging chain 36 and the horizontal position of the sightbar 62. Whenthe operator is digging a trench, if he is digging a trench to arelatively steep grade, he merely sights along the horizontallyextending portion of the sightbar 62 and visually checks to see if thesightbar 62 is at the same elevation as the preset datum plane. If thesightbar 62 is higher or lower than the datum plane, he makes anadjustment with the winch 56 and either raises or lowers the winch cable57 thereby raising or lowering the bottom of the digging chain 36.However, if he is working to an xtremely fiat grade, it is necessary totake periodical direct measurements between the sightbar 62 and thedatum plane, rather than relying solely upon visual checks.

Referring to FIGS. 1 and 2, a horizontal earth or soil conveyor 65 ismounted on the rear end of the vehicle 11. The conveyor 65 includes aconveyor chute 66 having a soil discharge opening 67. A screw conveyor68 is mounted for rotation within the chute 66 and is driven by a belt69 which is operatively connected to the driven shaft 50.

The location of the soil conveyor 65 adjacent the vehicle 11 is animprovement over prior art bucket type trenches. After the prior artbuckets were filled, they moved upwardly, over the top of the path andthe soil was discharged onto conveyors located on the far side of thevehicle. In the present invention, because the soil within the trench 39is removed with an open chain cutter, rather than buckets, the soil ismoved upwardly and is discharged upon the soil conveyor 65 after arelatively short travel. By utilizing the open type digging chain 36,and the earth backboard member 40, it is possible to achieve themaneuverability afforded by a vertical digging operation and at the sametime eliminate the undesirable bucket type conveyors.

Referring to FIGS. 1-3, an earth shield 70 is preferably mounted in thesupport frame 20 adjacent the vehicle 11. The earth shield 70 isgenerally rectangularly shaped having a U-shaped vertical cross section.The shield 70 includes opposed longitudinally exending sides 71 and aweb 72 extending between the opposed sides. The web 72 defines adischarge opening 73 which communicates with the soil conveyor 65. Theearth shield 70 terminates at a location below the chassis 16 and theupper end terminates below the idler pulley 42. The lower end of theearth shield 70 extends downwardly and terminates above the elevation ofthe ground. The earth shield 70 and the backboard member 39 define apassageway for the digging chain 36 and serves a dual purpose in that itnot only prevents unwanted discharge of the soil as it is carriedupwardly by the digging chain 36, but it also protects the operator frombeing injured by the digging chain 36. Referring to FIGS. 1-3, theexcavated earth is moved upwardly by the digging chain 36. Below theground elevation a portion of the backboard member 39 and the walls ofthe trench form a passageway for the excavated earth. Above the groundelevation a portion of the backboard member 39 and the earth shield 70form the passageway for the excavated earth. During operation, as thetrenching apparatus moves forward, a mound of earth forms below theshield 10 and serves as a wall portion of the excavated earthpassageway. The excavated earth is carried upwardly through thepassageway and is discharged through the opening 73 onto the conveyor65.

The trenching apparatus 10 has the advantages of being able to turn onan extrernly short radius and also, it is capable of digging throughhardpan or hard clay. When such soil conditions are encountered, ratherthan the rear wheels 13 losing traction, as is the case with the priorart cantilivered boom type trencher, the bite of the cutting teeth 37into the clay results in an additional downward force upon the rearwheels 13. Therefore, the traction is increased, rather than decreased.

A second embodiment of the present invention is shown in FIGS. 4 and 5.In this embodiment, the support frame 20 has an upper section 75 and alower section 76. Referring to FIG. 5, the upper section 75 is hinged tothe lower section 76 by hinges 77, which are mounted on the angles 21which are located adjacent the vehicle 11. On each of the angles 21 aconnecting flange member 78 is mounted at the meeting line between theupper section 75 and the lower section 76. The adjoining flange members78 on each of the angles 21 have indexing holes 79 extendingtherethrough and when the support frame 29 is in a generally verticaloperating position, as shown by the solid lines in FIG. 5, retainingbolts 80 extend through the adjoining holes 79 and secure the supportframe 20 in the upright position.

Referring to FIG. 4, a post 81 is pivotally mounted by a bracket 82 tothe front end of the vehicle 11. When it is necessary to move thevehicle 11 for a considerable distance, the post 81 is moved to thevertical position shown by the solid lines in FIG. 4. The retainingbolts 80 are then removed from the flange members 78 and the uppersection of the support frame 20 is pivoted downwardly until it reaches agenerally horizontal traveling position, as shown by the solid lines inFIG. 4.

While the present invention has been disclosed with a specificarrangement and disposition of the parts, it should be expresslyunderstood that numerous modifications and changes may be made withoutdeparting from the scope of the appended claims.

What I claim is:

1. In a trenching apparatus including a selfipropelled vehicle, theimprovement comprising, support means mounted adjacent the rear end ofsuch vehicle, said support means mounting a digger assembly for movementalong a generally vertical guide path, said digger assembly including achain support member and a closed loop digging chain mounted formovement on said chain support member, a generally vertical transverselyextending earth backboard member mounted interiorly of such chain loopand adapted to terminate below the ground, a generally verticalshielding member spaced forwardly from said earth backboard member, saidshielding member having a lower end terminating above the ground,wherein a portion of said earth backboard member and said shieldingmember define a passageway for excavated earth and wherein such chainloop travels through such passageway, earth removal means mountedadjacent such vehicle exteriorly and forwardly of such chain loop, meansfor driving said chain, and means for adjustably positioning said diggerassembly along such guide path.

2. Trenching apparatus, according to claim 1, in which said backboardmember is an integral part of said chain support member. 1

3. A trenching machine-according to claim 1, having a plurality of openbottomed cutting teeth positioned on said closed loop digging chain.

4. A trenching machine according to claim 3 wherein said earth removalmeans is a conveyor.

5. Apparatus according to claim 4 including means for correlating thevertical position of said digger assembly with respect to an establishedgrade, said correlating means comprising an outwardly extending sightbarmounted on said movable chain support member, said sightbar beingmounted on said support member a predetermined distance above the bottomof said digging chain.

6. A trenching machine according to claim 4 wherein said means foradjustably positioning said digger assembly comprises a cableoperatively connected to said chain support member and means for movingsaid cable.

7. A trenching machine according to claim 4 wherein said digger assemblyincludes a first chain sprocket mounted at one end of said chain supportmember and a second chain sprocket mounted at the other end of saidchain support member, said closed loop digging chain being mounted formovement on said first and second chain sprockets.

8. A trenching machine according to claim 4 wherein a discharge openingis defined by said shielding member adjacent said conveyor incommunication with the passageway defined by said earth backboard memberand said shielding member, whereby excavated earth is discharged throughsuch discharge opening onto said conveyor.

9. A trenching machine according to claim 4 wherein said support meanscomprises a vertically extending support frame.

10. Apparatus according to claim 9 wherein said sup port frame has amovable upper section and a stationary lower section, said upper sectionbeing pivotally mounted to said lower section and movable between agenerally vertical operating position and a generally horizontaltraveling position.

(References on following page) 7 8 References Cited 2,817,911 12/1957Owen et a1. 37-192 X 3,307,276 3/1967 Russcll 37192 X UNITED STATESPATENTS 3,006,087 10/1961 Lindell 37 192 x l/ 1913 Halle. 8/1936 VanVoorhis et a1. 37-83 5 ABRAHAM G. STONE, Primary Examiner. 4/1951Ekenstam 3790 1/1952 Przybylskii ANTONIO F. GUIDA, Exammer. 2/1954 Askue37-191 X A- E. KOPECKI, Assistant Examiner.

